By Penelope Patsuris

Imagine having a 17-inch screen constantly at your disposal that lets you look up information online, check your e-mail or watch a movie--and that isn't attached to a laptop.

Soon, thanks to the burgeoning microdisplay industry, you probably will.

Small liquid crystal displays are already ever-present on our cell phones, digital cameras, MP3 players and PDAs. But scientists and startups alike have figured out how to make tiny wearable screens--with diagonals of less than half an inch--project what looks like a lifesize screen floating in space just a couple of feet from your eyes. These devices permit the wearer to remain totally engaged with their environment, able to see everything around them. The trick is in the magnifying optics on top of the display, which creates the illusion of a large, legible monitor that moves with you when you move your head.

"People have been talking about this kind of thing for ten years," says John Fan, chief executive of Kopin (nasdaq: KOPN - news - people ), which makes these tiny displays. "But now the technology is here and it has the right price point." The Taunton, Mass., outfit is one of the biggest makers of the microdisplays that are embedded into digital cameras made by Matsushita (nyse: MC - news - people ) and JVC, and also counts the U.S. Army, Hitachi (nyse: HIT - news - people ) and Agilent (nyse: A - news - people ) as customers.

Another Kopin customer is Westwood, Mass.-based MicroOptical, which sells small screens that surgeons can clip onto their glasses so they can glance at a patient's vital signs without having to lift their heads. These screens, often referred to as "heads up" displays, are used extensively by the military, which is loading soldiers up with displays that help them do everything from seeing around corners to referencing global positioning maps.

Interactive Imaging Systems, based in Rochester, N.Y., is rolling out a new personal display product called Second Sight that also uses Kopin displays and will be aimed at industrial users. CEO Paul Travers explains that the head-mounted displays are meant to be used by engineers working on aircraft or other heavy machinery who usually have to climb back and forth to a computer to log their repairs and check various data.

A "heads up" display from MicroOptical

Right now, such eyewear is bulky and has a small protruding screen, but these companies say that won't always be the case. For instance, MicroOptical is backed by and partners with France's Essilor International. One of the biggest eyeglass companies in the world, Essilor makes the popular Varilux brand and is known for its durable lightweight lenses.

"In the future, electronic eyewear will have to be like sunglasses, which perform a function but also look cool," says MicroOptical Marketing Vice President Mark Basler. For starters, that means the screens won't stick out, but rather will be embedded into the frames. Basler says that eventually these glasses will be wirelessly connected to the handhelds that our phones, Apple Computer (nasdaq: AAPL - news - people ) iPods and PalmOne (nasdaq: PLMO - news - people ) PDAs will ultimately morph into.

These glasses are not to be confused with the "immersion" eyewear that's long been used to simulate virtual reality. "You can't use those when you're walking around, but you will be able to do just that with our eyewear," says Basler.

"We've talked to a lot of wireless telecom executives, and they're very interested in replacing cell phone displays with these kinds of glasses," Basler says. "These companies want to be able to sell consumers more and more display-intensive functions that will use up air time, but in order to do that they'd have to make the handsets so big that no one would buy them. That's where we come in." Possible partners also include phone makers like Motorola (nyse: MOT - news - people ), Nokia (nyse: NOK - news - people ) and Samsung.

Microdisplay executives love to cite the example of consumers wearing these special glasses to watch their favorite DVDs privately while sitting on a train or bus. And that's a possibility.

But the reality will probably be a lot more interesting. Thad Starner, an assistant professor of computing at the Georgia Institute of Technology, has been using a heads-up display that he built, along with a wearable computer, since 1993. "I was wearing a mobile computer when laptops were just coming out, and people were wondering why anyone would want [a laptop]," he says. "That's because they were still thinking in terms of spreadsheets." Now, of course, most of us use laptops and PDAs to do all sorts of things on the go, including access the Internet.

Starner expects that the advent of mass-market floating displays will similarly expand what we do with mobile computers. He and his peers predict that someday we'll all be operating in "augmented reality" with the help of our wearable computers. All that really means is we'll eventually have the ability to bring the Web--or some form of it--with us wherever we go.

Indeed, Starner already does exactly that, using his Sprint (nyse: FON - news - people ) Internet connection. "Being able to look stuff up wherever you go is really powerful," he says. He imagines being able to walk up to a restaurant and look up its latest Zagat rating. "The trick is to make displays that you can get valuable information from by having to look at the least amount of information possible," he says.

That points to the biggest challenge in the quest for truly mobile personal displays: a suitable design. The technology may be here, but, says Starner, "there's a lot to be said for getting the form factor right."